KVPY2020MathematicsHeights and Distances
A person standing on the top of a building of height 60 3 feet observed the top of a tower to lie at an elevation of 45 ° . That person descended to the bottom of the building and found that the top of the same tower is now at an angle of elevation of 60 ° . The height of the tower (in feet) is
Options
- A30
- B30 ( 3 + 1 )
- C90 ( 3 + 1 )
- D150 ( 3 + 1 )
Correct answer
C. 90 ( 3 + 1 )
Step-by-step solution
60 3 + d d = 3 ⇒ d = 60 3 3 - 1 ⇒ h = 60 3 1 + 1 3 − 1 = 60 × 3 3 − 1 = 90 ( 3 + 1 )